by Eric Helms, Ph.D.

Dieters who leverage flexible restraint get better outcomes, but how? In this article, you’ll learn how to move beyond the spreadsheet and leverage key evidence-based concepts to autoregulate a dietary approach that can lead to fat loss, or even bodybuilding stage condition.

Key Points

1. “Flexible dieting” or “IIFYM” presupposes certain skills. The research-based concept of “flexible restraint” is more nuanced, relates to diet success, and involves “diet autoregulation,” but its success also depends on an often unspoken set of competencies.
2. Diet autoregulation is not “intuitive eating,” but goal-directed eating built on: nutritional competence (knowledge + practical skill), interoceptive awareness (perceiving internal body signals), and self-regulation (acting on information objectively).
3. These are not innate traits, but trainable. With practice, dieters and even physique athletes can develop responsive, sustainable, autoregulated gaining and fat loss approaches.

The Problem with “Flexible Dieting”

The fitness industry’s popular version of “flexible dieting,” often expressed as “If It Fits Your Macros” (IIFYM), promises freedom from the rigid “good food/bad food” dichotomy. While a step up from overly restrictive clean-eating food lists (which unfortunately still persist in popular culture), it’s a system that can fail in practice when users or coaches don’t realize that it implicitly requires a high level of prerequisite skills that are rarely taught alongside it. It presupposes not only a deep understanding of energy balance and macronutrients but also the practical competence to track accurately, weigh foods, use tracking apps, understand the limitations of their databases, and a basic understanding of how cooking methods impact energy and food mass. On top of that knowledge, successful long-term adherence to flexible dieting is contingent on having skill in accurately estimating portions, especially when not preparing your own foods, and choosing foods that not only hit one’s target macros, but also which manage satiety, energy, and micronutrient needs. Needless to say, IIFYM is not something anyone can just pick up and be successful with.

The academic literature, however, has a more nuanced concept than IIFYM called “flexible dietary restraint,” first proposed by Westenhoefer in the 1990s (1), which stands in contrast to “rigid dietary restraint.” Since the origination of this supposed dichotomy decades ago, a large amount of observational research has shown that individuals who practice flexible restraint – viewing foods in a non-dichotomous way and focusing on moderation – achieve better long-term weight management outcomes with a lower probability of developing body image concerns or eating disorder symptoms than those who practice rigid restraint (2). Notably, this literature implies that not being as strict and moderating portion sizes and caloric intake on a day-to-day basis – what could be described as diet autoregulation – results in better outcomes. However, most of the studies on flexible restraint are correlational and without an identified mechanism, meaning the ability to apply flexible restraint could reflect innate traits of these individuals. These studies beg the question, how do those with flexible restraint actually achieve success? Is it just a natural mindset, or is it contingent on underlying skills?

A 2025 study by Nicholls and colleagues, the most recent innovation in the study of flexible and rigid restraint, provides a clue (2). In developing a newly validated scale to better differentiate flexible from rigid restraint (a differentiation which has been questioned in recent research as I discussed here), they identified several reliable sub-components of each type of restraint. For example, their “Flexible Beliefs” subscale seems to require some foundation of nutrition knowledge, rather than being purely contingent on personality traits related to moderation, as it contains questions such as “I think that any food is okay to eat occasionally” and “I think that any food is okay to eat in small amounts.” Many come to hold “flexible beliefs” like this once they get nutrition education, or have misinformation corrected, such that they understand energy balance and its relation to body composition. Likewise, the authors’ “Worry” subscale is likely inversely related to the psychological construct of self-efficacy, which is a cornerstone of self-regulation (3; which I’ll discuss in depth), as this sub-scale contains questions such as “I worry that I will lose control over how much I eat,” “I worry that I will lose control over what I eat” and “I feel like food controls me, rather than the other way around.” The relationships observed by Nicholls open up the possibility that successful flexible restraint may not just be a fixed personality trait or an attitudinal disposition towards moderation, but may be the outcome of (or at least influenced by) the development of specific competencies. Thus, the rest of this article will deconstruct these competencies, providing a theoretical framework and a practical guide to what is happening “under the hood” during successful diet autoregulation, so that you have a roadmap to developing or helping others develop the ability to implement it.

The Three Pillars of Autoregulation

I conceptualize successful autoregulated dieting as a high-level skill built on three distinct, interconnected, trainable pillars: nutritional competence, interoceptive awareness, and self-regulation (Figure 1). A common colloquial discussion of diet autoregulation in fitness-oriented conversations often results in framing it as “intuitive eating.” While I get the use of this off-the-cuff description, it’s important to understand that in research and clinical practice, Intuitive Eating describes a specific weight-neutral eating framework designed to repair one’s relationship with food and break the cycle of eating disorders, it is not a goal-directed approach to dieting. As described by Tylka and colleagues (4) “Intuitive eating entails eating mainly in response to physiological hunger and satiety cues—those who eat intuitively are attuned to and trust their hunger and satiety signals to guide their eating (Tylka, 2006). If such individuals eat more at one meal, they may naturally eat less at the next meal because they are less hungry; therefore, intuitive eating has been described as a flexible and adaptive eating behavior (Tribole & Resch, 2012). Tribole and Resch assert that individuals who eat intuitively are less likely to be preoccupied with food or dichotomize food as good or bad—instead, they often choose foods for the purposes of satisfaction (i.e., taste), health, energy, stamina, and performance.” 

Thus, while intuitive eating is qualitatively distinct from diet autoregulation as it is explicitly not a tool for fat loss, success with either framework relies on some of the same principles and skills. Figure 1 visualizes the relationship between the three pillars of diet autoregulation, which I will discuss in depth next. Further, it’s important to understand, and easy to recognize in real-world examples, that this system is likely to fail if any of these pillars is underdeveloped or absent.

Nutritional Competence 

This pillar represents the fusion of theoretical knowledge and practical skill. It’s not enough to simply know that a calorie deficit is required for fat loss; you must have the competence to enact that knowledge. This pillar is heavily contingent on both knowledge, and practical skills. Nutritional competence includes knowing that energy balance and macronutrients regulate body composition and how adjusting energy intake and output are likely to influence body composition. But, nutritional competence also includes the skill of accurately estimating portion sizes of various foods cooked in various ways without a scale, so that you can autoregulate your diet in many environments. You need the knowledge of appropriate rates of weight loss, but also the skill of how to evaluate average weigh-ins over different time periods, high and low weigh-ins, the influence of high sodium intakes, training sessions that cause muscle-damage, diets of the same energy and macronutrient intake but differing in energy density and therefore food weight, and the influence of weighing in at different times of day. 

As an analogy, you can read about weightlifting to understand how an optimal snatch or clean and jerk is performed biomechanically, but actually mastering the snatch or clean and jerk requires years of practice in the weight room. This distinction between knowledge and skill is critical. As demonstrated in a 2023 study on maternal malnutrition in Ethiopian pregnant women by Wakwoya and colleagues, providing nutrition education alone is not as effective as pairing it with counseling that builds the skills and competence to apply that information (5). Specifically, the authors evaluated the effect of intensive nutrition education and counseling on nutritional status during pregnancy in a one-year randomized controlled trial of 374 participants. Half received three counseling sessions by trained midwives, take-home brochures, and 18 weekly serial short text messages, while the other half received routine nutrition education from the health facilities. At the end of the trial, women in the information and counselling intervention group had significantly better markers for nutritional status than those only receiving information.

In the context of dieting, this is the pillar that expands your ability to diet in a greater variety of environments and circumstances, improving adherence. This pillar allows you to make informed decisions on the fly – to know which item on a restaurant menu is a better choice, or how to adjust your intake after an unexpectedly large meal or sedentary day. To link this pillar back to two theoretical, evidence-based concepts of behavior change that Dr. Zourdos and Dr. Trexler covered in MASS, this competency directly builds your Capability, a cornerstone of the COM-B model of behavior change (6), and fosters the self-efficacy, or task-specific confidence, that is central to Social Cognitive Theory (3). However, to truly autoregulate a diet in as responsive a way as possible, using not only objective, external cues which can only be so accurate, requires interoceptive awareness. 

Interoceptive Awareness 

The pillar of interoceptive awareness is your ability to accurately perceive and interpret your body’s internal signals: hunger, satiety, fatigue, energy levels, and even the “flatness” or “fullness” of your muscles (indicating muscle glycogen status). It is the primary dataset for real-time autoregulation. While nutritional competence can be developed through formal education, reading, online learning, hands-on educational workshops and spending some time tinkering with tracking apps, reading nutrition labels, and using food scales even without actually dieting, applying interoceptive awareness to diet autoregulation requires specific experience. For example, to actually autoregulate a diet to stage condition as a bodybuilder, you must have the experience to differentiate appropriate levels of hunger at different stages of contest prep. For example, when you are extremely lean, eating at maintenance will result in less post-meal satiety, higher levels of baseline hunger, and more food focus between meals than when you are higher in body fat. Essentially, eating at maintenance when you are really lean is experientially like being in a deficit when you aren’t as lean. This reality is why weight regain is the norm among most dieters, and why modern GLP-1 obesity medications which curb this “food noise” are so effective. To autoregulate a diet all the way to very low body fat using interoceptive awareness, you must be able to distinguish between the qualitative experiences of being at maintenance, in small, moderate, or large surpluses or deficits, respectively, and do so across your personal body fat spectrum (and in interaction with various food environments).

But let’s take a step back and discuss interoceptive awareness more broadly and in view of the emerging evidence. While in my anecdotal personal and coaching experience interoceptive awareness seems to be a trainable skill, only recently has research attempted to discern whether it truly is or is more of an innate trait. A 2022 study by Palazzo and colleagues provides direct evidence for its trainability, finding that a mindfulness-based “food consciousness” intervention directly improved participants’ interoceptive sensitivity (7). The 3-4 week study recruited women who specifically struggled with weight maintenance. Out of an initial 54 participants, 37 completed the trial (19 in the intervention group; 18 in the control group). The intervention group attended four two-hour workshops one week apart covering topics such as the senses and the desire to eat, food pleasure, and how to deal with internal body signals like hunger and satiety. They also completed three at-home workshops between meetings. The control group had a 3-4 week non-interventional waiting period between pre-and post testing which consisted of two outcome measures: 1) interoceptive perception via a commonly used heartbeat counting accuracy task and 2) an exteroceptive perception task in which the participants wrote descriptive words after eating three foods, and the words were quantitatively analyzed to determine the richness of their description. At the end of the trial, the intervention group significantly improved both the accuracy of their interoceptive awareness and their ability to richly describe their sensory food experiences compared to the control group. This demonstrates that interoceptive skills can be deliberately and measurably developed through focused practice over a relatively short period.

Taking this a step further, a 2023 randomized clinical trial by Loucks and colleagues demonstrated that a mindfulness program designed to enhance interoceptive awareness led to significantly better adherence to a structured dietary plan (8). In this trial, 201 adults with elevated blood pressure were randomized to either an 8-week mindfulness-based blood pressure reduction program (n = 101) or an enhanced usual care control group (n = 100). The program consisted of an orientation, eight weekly 2.5-hour group sessions, and a single 7.5-hour group session, and recommended at-home mindfulness practice for at least 45 minutes per day, six days per week. The program generally trained participants in interoceptive awareness via mindfulness practices such as body scan exercises, meditation and yoga, and also specifically focused their awareness to hypertension risk factors such as overconsumption of and cravings for palatable foods, changing sedentary activities, reducing alcohol consumption, and medication adherence. Specifically related to diet, participants were trained to bring awareness to their emotions, thoughts and physical sensations prior to, during, and after eating. After six months, the mindfulness group not only significantly improved their interoceptive awareness, but also their adherence to the DASH (Dietary Approaches to Stop Hypertension) diet compared to the control group. Furthermore, their exploratory mediation analysis provided preliminary indication that improvements in interoceptive awareness at least partially led to better dietary adherence. To conclude, this study provides a powerful empirical link for the analytical lifter to bolster my anecdotal coaching and personal experience: developing the “soft skill” of listening and better interpreting your body signals though mindfulness training leads directly to the “hard outcome” of better and more consistent dietary adherence. 

Most relevant to the proposed framework of diet autoregulation, is the theoretical basis Loucks and colleagues proposed for their intervention (Figure 3). They hypothesized a mindfulness intervention would enhance self-regulation via improved interoception (i.e., self-awareness, attention control, and emotional regulation) and increase success with the DASH diet. Similarly, my currently proposed framework centrally leverages the concept of self-regulation.

Self-Regulation 

This is the final and arguably most crucial pillar. It is the ability to take the information provided by your nutritional competence and interoceptive awareness and act on it in a way that is objective, non-emotional, and aligned with your long-term goals. It’s the skill that allows you to acknowledge a strong hunger signal but decide not to act on it because it doesn’t align with your goals for the day, or conversely, to decide to eat more despite not feeling hungry because your biofeedback indicates a refeed is necessary.

Like interoception, research demonstrates that self-regulation is also a trainable skill. A 2025 study by Lopez and colleagues provides evidence that training individuals in several self-regulatory strategies can directly improve their healthy eating behaviors in multiple domains (9). In this longitudinal intervention, 360 participants were trained to use one of two classes of self-regulatory strategies: situation-based strategies (e.g., hiding tempting foods to avoid cues) or cognitive reappraisal (e.g., reframing the thought of a tempting food to reduce its emotional appeal), and then applied those strategies to either encouraging healthy eating, or discouraging unhealthy eating. The study began with a baseline assessment of the participants’ ability to regulate their dietary cravings, followed by training in one of the two self-regulation strategies (or no training in the control group), followed by daily assessments over two weeks to assess the short-term impact of self-regulation training on hunger, dietary intake, strength of cravings, and the use of the self-regulation strategies in their day-to-day lives. Then, to assess the long-term effectiveness of self-regulation, the participants repeated these assessments one and two months later. 

Overall, the researchers found that participants who trained in and subsequently used either self-regulatory strategy reported higher success in healthy eating (either eating more healthy food or less unhealthy foods, with some limited transfer effects between approaches). This study is crucial because it moves beyond the correlational data which dominates this area of study to provide direct, causal (albeit preliminary and of modest strength) evidence that self-regulation is a skill that can be taught and that its application leads to better dietary outcomes. 

However, the proverbial “proof in the pudding” for physique athletes comes from a 2024 study by de Moraes and colleagues (10) that I reviewed back in Volume 8. Researchers observed the final week of 14 Brazilian bodybuilders’ offseason and the first four weeks of their contest preparation dieting phase during which the athletes had two ad libitum, untracked “cheat meal” refeeds each weekend. Relevant to the present article, the outcomes the researchers measured consisted of a battery of validated questionnaires to assess the athletes’ mindful and intuitive eating scores, emotional coping strategies, and correlated these with their actual energy intake during the cheat meals. The athletes who ate fewer calories in their cheat meals had higher intuitive eating scores, specifically in their confidence in hunger and satiety signals and body-food congruence, and better emotional coping skills. 

This finding directly supports the idea that interoceptive awareness and self-regulation are key to unlocking the ability to handle dietary flexibility in the specific context of contest prep. Further, given the fact that these were experienced competitive bodybuilders (averaging over 10 years of training and 6 competitions), they likely had high nutritional competence, supporting all the underlying concepts in my proposed framework of diet autoregulation. 

When the System Fails: Missing Pillar

To further bolster the proposed framework, consider how the interdependence of these three pillars explains the most common types of prep failures we see in physique athletes and dieters.

Lacking Nutritional Competence

This is the dieter who has good self-control and is in tune with their body, but consistently stalls. These are the bodybuilders out of touch with modern, evidence based approaches. They follow “good food, bad food lists,” simply don’t diet long enough (follow the old school 12-week approach), and might not understand the key role of energy balance in fat loss. They might choose an avocado and a handful of almonds for a snack, thinking it’s a “healthy” or “clean” choice, without understanding that its high energy density has put them out of their calorie deficit. 

Lacking Interoceptive Awareness

This is the classic, rigid “IIFYM” dieter. They have the nutritional knowledge to build a perfect spreadsheet and the self-regulation to hit their macros to the gram. However, they are completely disconnected from their body’s signals of crippling fatigue, poor sleep, and ravenous hunger. They “trust the spreadsheet” over their own biology, which often leads to burnout, metabolic adaptation, and a severe rebound post-diet. They might come in very lean, but lose muscle in the process, or come in flat or spilled over as they don’t autoregulate in peak week when you have to be dynamic and responsive. 

Lacking Self-Regulation

This is the knowledgeable dieter who is aware of their internal signals but is consistently derailed by emotion. They know they aren’t truly hungry, but after a stressful day at work, they turn to food for comfort. Or, they feel a slight dip in energy and immediately panic, leading to an unplanned and oversized refeed. They struggle with emotional eating or anxiety driven decisions that aren’t in their best interest. They can sense their internal signals, they understand nutrition fundamentals, but they can’t control the tumultuous nature of their emotional responses during contest prep and look back in hindsight at the errors they made and see how they went wrong. 

How to Start Implementing Diet Autoregulation 

The ability to autoregulate a diet is not a mysterious talent reserved for the genetically gifted or the decade-plus veteran. It is the outcome of developing a specific, multi-faceted skill set. Successful autoregulation requires the nutritional competence to make informed choices, the interoceptive awareness to listen to your body’s biofeedback, and the self-regulation to act on that information objectively. The research is clear: these are not fixed traits, but trainable skills. Interventions have improved nutritional competence (5), interoceptive sensitivity (7), and self-regulatory strategies (9), and contest prepping bodybuilders with these skills can moderate their energy intake to a greater degree when consuming food ad libitum (10). By viewing your dieting journey – especially if you start in the offseason – as a deliberate opportunity to practice these skills, you can move beyond a rigid reliance on external tools and develop a more agile, responsive, and ultimately more sustainable approach to achieving your physique goals.

To start this process, both the athlete and the coach must first understand and buy into the three pillars framework. Many athletes operate under the belief that internal signals like hunger and fatigue are obstacles to be fought, ignored, or “toughed out” on the path to getting shredded. The first and most critical step is a paradigm shift: recognizing that these internal cues are not enemies of the diet, but valuable data points that can be used to monitor and autoregulate for better fat loss, muscle retention, and long-term adherence in the sport.

Once this framework is seen as desirable, the next step is to identify which pillars are lacking. While most people need to work on all three, the emphasis will depend on the individual. An athlete with a master’s degree in nutrition may have exceptional nutritional competence but no practical experience with contest prep. They will need to deliberately develop their interoceptive awareness within the specific context of getting very lean to learn what appropriate levels of hunger and fatigue feel like at different stages. Conversely, an experienced competitor who consistently misses their peak might have a great feel for their body but lacks the self-regulation to manage the final, difficult stages of a diet, or the nutritional competence to make precise adjustments.

The development of these skills should be approached progressively. An athlete can fast-track their ability to autoregulate by starting in the offseason, then practicing in a less demanding mini-cut, and finally applying the skills in increasingly comprehensive ways during successive contest preps. The initial phase should focus on correlation. Use external tracking tools (food scales, apps, daily weigh-ins) as your guide, but with the explicit goal of paying attention to how they relate to your internal cues (hunger, energy, sleep, mood, food focus). A coach can be invaluable here, helping an athlete learn to recognize patterns between deficit size and gym performance, or how to interpret scale weight fluctuations in the context of sodium intake, carb-ups, or the menstrual cycle, and simply providing the athlete encouragement, support, and confidence while they navigate the unfamiliar and intimidating process of autoregulation.

After a first prep where external cues lead and internal cues are simply observed, the roles can begin to flip. In the next prep, internal cues can become a more prominent tool for autoregulation. This can be approached in a quantitative or a more qualitative manner. An analytical athlete might create an algorithm-like flowchart, using 1-5 ratings for hunger, energy, sleep, and performance to guide decisions on when to refeed or adjust calories. Another might use a less structured system, making an overall qualitative assessment of the same inputs to adjust their meal plan. Most will use a mixed approach, combining quantitative data like rolling weight averages with subjective feelings of fullness and energy.

Ultimately, by deliberately deciding to use this framework, targeting which skills need to be developed, and then incrementally practicing them in increasingly challenging situations, an athlete can master autoregulation. By moving from simply correlating the internal to the external, to progressively relying more on internal cues, one can utilize these seemingly “advanced” skills to maximize performance and sustainability much faster than through passive experience alone. In my experience, a dedicated athlete can achieve a high level of autoregulated ability as early as their third season. The real challenge for many bodybuilders, however, is finding the courage to try a system that initially feels like a loss of control (but ultimately results in greater control).

References

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3. Bandura, A. Social cognitive theory of self-regulation. Organizational behavior and human decision processes. 1991;50(2):248-87.
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9. Lopez RB, Werner KM, Traub G, Saunders B, Cosme D, Hofmann W. Training self-regulation to promote healthy eating: Evidence from a longitudinal intervention study. Appetite. Published online September 16, 2025.
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